Use of += on a private String in a nested class causes IllegalStateException when imported #1146
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Thanks for reporting this issue in such great detail! I had a quick look and can reproduce it thanks to your demo repository – which highly appreciated. 💚 |
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I had a look at it and I think the Stringbuilder is not the problem, at least not directly. To me it seems that the synthetic access is not registered correctly or cannot be resolved. Right now I do not fully understand it, but will investigate further :) |
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FYI: |
codecholeric
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Dec 3, 2023
We weren't aware that the compiler occasionally generates synthetic
`access$123` methods that call constructors. More precisely for the
following constellation
```
class Outer {
String field = "";
class Inner {
void concat() {
field += "any";
}
}
}
```
the compiler generates bytecode instantiating and using a
`StringBuilder`. But for constructor calls the synthetic access
resolution was not hooked in, because we assumed that those methods
would never call a constructor. This in turn lead to the bug
```
java.lang.IllegalStateException: Never found a JavaCodeUnit that matches supposed origin CodeUnit{name='access$123'...
```
I.e. the method `access$123` was filtered out as synthetic, but the
origin of the constructor call had not been resolved to the actual
`Inner.concat` method.
Resolves: #1146
Resolves: #1194
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JDK version: Amazon Corretto 11.0.16
Java Source/Target version: 8
ArchUnit version: 1.0.1
At least this version of the JDK, when targeting Java 8, replaces uses of += with StringBuilder in a way that results in a synthetic access method being created that ArchUnit doesn't seem to know what to do with.
Here's a class, that when imported, that triggers the error in ArchUnit
The following test will fail with the below error
java.lang.IllegalStateException: Never found a JavaCodeUnit that matches supposed origin CodeUnit{name='access$084', descriptor=(LOuter;Ljava/lang/Object;)Ljava/lang/String;, declaringClassName='Outer'}Full Stack Trace:
This implementation will pass the test
Debugging into ArchUnit, I saw that the
RawAccessRecordcontaining theCodeUnitmentioned in the error had a target that mentionedStringBuilder, which isn't anywhere in the original code. However, if you look at the bytecode, the compiler has decided to replace the use of+=and use aStringBuilderinstead. According to the Java Language Spec, this is allowed.This is a bytecode disassembly showing use of StringBuilder
A complete repro is available at https://github.com/OneGeek/archunit-bug-repro/ , which includes tests that import classes implemented with and without the use of
+=. Only the one without passes.The text was updated successfully, but these errors were encountered: